BIO1011 Week 3 Building Life: The Evolution of Diversity

These flashcards cover key vocabulary relevant to the learning outcomes of the BIO1011 Week 3 lecture, focusing on cellular structures, functions, and evolutionary concepts.

Prokaryotic cell

A type of cell that does not have a nucleus or other membrane-bound organelles, characterized by its simple structure.

Eukaryotic cell

A type of cell that has a nucleus and other membrane-bound organelles, typically more complex than prokaryotic cells.

Passive transport

Passive transport is the movement of molecules across a cell membrane without the use of cellular energy. This process occurs along the concentration gradient, meaning substances move from areas of higher concentration to areas of lower concentration. It includes various mechanisms such as diffusion, facilitated diffusion (which involves carrier proteins), and osmosis (the movement of water molecules). Since energy is not required, passive transport is a vital process for maintaining homeostasis in cells.

Active transport

Active transport is the movement of molecules across a cell membrane against their concentration gradient, which requires the expenditure of energy, usually in the form of ATP (adenosine triphosphate).

This process is essential for maintaining cellular homeostasis and allowing cells to uptake nutrients, ions, and other substances necessary for cellular functions. There are two main types of active transport: primary active transport, which directly uses energy from ATP, and secondary active transport, which utilizes the energy from the electrochemical gradient created by primary active transport. Examples of active transport include the sodium-potassium pump, which transports sodium out of the cell and potassium into the cell, and the proton pump, which helps in maintaining pH levels within cells

Osmosis

It refers to the movement of water across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Osmosis is vital for processes such as nutrient absorption, waste removal, and overall homeostasis.

Diffusion

The process of movement of particles from an area of higher concentration to an area of lower concentration.

The rate of diffusion is influenced by several factors including temperature (higher temperatures increase kinetic energy and diffusion rate), concentration gradient (a steeper gradient results in faster diffusion), and the size of the particles (smaller particles diffuse more quickly).

It is also a passive transport mechanism, meaning it does not require energy input to occur

Amphipathic

Molecules that have both hydrophilic (water-attracting) and hydrophobic (water-repelling) properties.

Homeostasis

The ability of a cell or organism to maintain a stable internal environment despite external changes.

Homeostasis is crucial for the survival of organisms since cells operate best within a narrow range of conditions. For example, in humans, the normal body temperature is around 37°C (98.6°F), and various mechanisms, such as sweating or shivering, help to regulate temperature in response to changes in the environment.

Phylogenetic tree

A diagram that shows the evolutionary relationships among various biological species based on their physical or genetic characteristics.

Horizontal gene transfer

The transfer of genetic material between organisms in a manner other than conventional reproduction.

This form of genetic exchange is prevalent in prokaryotes, such as bacteria, but also occurs in some eukaryotes.

Cholesterol

A type of lipid that is essential for the structure and function of cell membranes, affecting membrane fluidity.

Cholesterol is crucial for maintaining membrane fluidity, which is the ability of the membrane to remain flexible and functional at various temperatures.

At high temperatures, it prevents the membrane from becoming too fluid, while at lower temperatures, it helps to prevent the membrane from becoming too rigid

Genome

The complete set of genes or genetic material present in a cell or organism.

Archaea

Single-celled microorganisms that are prokaryotes, distinguished from bacteria by genetic and biochemical differences.

They possess unique features, such as the presence of ether-linked lipids in their cell membranes

Bacteria

Single-celled prokaryotic microorganisms, some of which can be pathogenic.

They reproduce asexually through binary fission, a process in which a single cell divides into two identical daughter cells, allowing for rapid population growth under favorable conditions.

Transport protein

Proteins that assist in the movement of substances across a cell membrane.

1. Channel Proteins: These proteins form water-filled passages that allow specific ions and molecules to diffuse across the membrane according to their concentration gradients. For example, ion channels are specific to ions such as sodium, potassium, calcium, or chloride, enabling rapid transport of these ions in and out of cells.

2. Carrier Proteins: Unlike channel proteins, carrier proteins bind to specific molecules and undergo conformational changes to transport these molecules across the membrane. This process can be passive (facilitated diffusion) or active, where energy (usually in the form of ATP) is required to move substances against their concentration gradient. An example is the glucose transporter, which helps cells absorb glucose from the bloodstream.

Facilitated diffusion

The process of spontaneous passive transport of molecules across a membrane via specific transmembrane proteins known as transport proteins.

This mechanism does not require energy (ATP) because it relies on the concentration gradient, allowing substances to move from an area of higher concentration to an area of lower concentration until equilibrium is reached.